Guanosine inhibits hepatitis C virus replication and increases indel frequencies, associated with altered intracellular nucleotide pools.

In the course of experiments aimed at deciphering the inhibition mechanism of mycophenolic acid and ribavirin in hepatitis C virus (HCV) infection, we observed an inhibitory effect of the nucleoside guanosine (Gua). Here, we report that Gua, and not the other standard nucleosides, inhibits HCV replication in human hepatoma cells. Gua did not directly inhibit the in vitro polymerase activity of NS5B, but it modified the intracellular levels of nucleoside di- and tri-phosphates (NDPs and NTPs), leading to deficient HCV RNA replication and reduction of infectious progeny virus production. Changes in the concentrations of NTPs or NDPs modified NS5B RNA polymerase activity in vitro, in particular de novo RNA synthesis and template switching. Furthermore, the Gua-mediated changes were associated with a significant increase in the number of indels in viral RNA, which may account for the reduction of the specific infectivity of the viral progeny, suggesting the presence of defective genomes. Thus, a proper NTP:NDP balance appears to be critical to ensure HCV polymerase fidelity and minimal production of defective genomes.

Ocular Trauma Characterization in a Reference Emergency Eye Centre in Colombia (FOSCAL).

BACKGROUND: Ocular trauma is one of the most important causes of ocular morbidity and inadequate visual acuity in developed and developing countries. In some countries, eye trauma is the leading cause of monocular blindness. Studies conducted in developing countries like Colombia suggest that there is a lack of awareness of preventive measures. In Colombia, there is no countrywide ocular trauma registry. The purpose of the present study is to describe and analyse characteristics of ocular trauma at a tertiary ophthalmology emergency department in Colombia. PATIENTS/METHODS AND MATERIAL: Patients who consulted or were referred to the ophthalmologic emergency department of FOSCAL due to eye injuries between March 1, 2022, and January 10, 2023, were included in this cross-sectional study. RESULTS: Of 1 957 patients, 2 088 eyes were included. Men comprised 78.5% of the patients, the median age was 36 years, and 75.0% lived in urban areas. The median latency between trauma and ophthalmology consultation was 21.8 hours. Of the eyes, 1 805 (88.4%) had suffered mechanical or mixed (mechanical plus burn) trauma. Of the injuries, 87.5% were unilateral. In terms of the circumstances, 45.9% of injuries occurred during working or educational activities (in 85.6% of these cases, without eye protection), 28.2% in home accidents, and 14.0% in transportation situations. According to the Birmingham Eye Trauma Terminology System (BETT), 1 735 eyes (91.1%) were closed globe injuries, and 49 eyes (2.7%) were open globe injuries. Fifty eyes (2.8%) could not be categorised according to BETT at the initial consultation and were classified as "still to be determined". In the Ocular Trauma Score (OTS), 85.8% were category 5. Of the ocular burn cases, 93.0% were categorised as grade I according to the Roper Hall classification. CONCLUSIONS: In line with global literature, a much higher proportion of men than women sought consultation for ocular trauma. The findings suggest a need for improvement in the referral process from institutions with the lowest level of care. Lack of awareness about eye protection is an issue. Surgical exploration or additional tests may be necessary for precise injury classification. We therefore propose adding a "still to be determined" category to the BETT initial classification. These cases may be reclassified later, thus improving the accuracy of OTS calculation.

Clinical Features and Neurodevelopmental Outcomes for Infants with Perinatal Vertical Transmission of Zika Virus, Colombia.

Transplacental transmission of Zika virus has been reported during all trimesters of pregnancy and might lead to central nervous system anomalies, including microcephaly. We report 3 cases of perinatal Zika infection identified during the epidemic in Colombia and provide detailed descriptions of clinical features, diagnosis, and neurodevelopmental outcome at 18 months of age (corrected).

Fetal central nervous system anomalies according to RT-PCR and trimester of maternal infection with Zika virus: A prospective cohort study.

INTRODUCTION: In October 2015, an epidemic of Zika began in Colombia's geographic areas with a high population of mosquitoes of the genus Aedes. We aimed to describe the fetal brain ultrasound findings in pregnant women with active symptoms or a history of symptoms suggestive of Zika virus (ZIKV) infection. MATERIAL AND METHODS: Eligible pregnant women were tested with reverse transcriptase-polymerase chain reaction (RT-PCR) for ZIKV and followed prospectively using detailed anatomic ultrasound and transvaginal neurosonography to detect structural anomalies of the fetal central nervous system (CNS). RESULTS: A total of 115 symptomatic women with a positive ZIKV RT-PCR and 55 with a negative ZIKV RT-PCR were enrolled in the study; CNS compromise of the fetus occurred in 22% and 17%, respectively (p = 0.255). Callosal dysgenesis (14.5%) was the most frequent anomaly of the CNS, followed by microcephaly (13.6%) and neuronal migration disorders (8.3%). When symptomatic ZIKV RT-PCR-positive women were categorized by trimester of infection, CNS anomalies were present in 40% of first-trimester infections, compared with 21% and 7% in second- and third-trimester infections (p = 0.002). CNS anomalies were also more severe in first-trimester-infected fetuses than in second- and third-trimester-infected fetuses. The high prevalence of CNS anomalies in fetuses of symptomatic ZIKV RT-PCR negative women suggests a high rate of false-negative cases and an even higher prevalence of CNS anomalies than observed in this study. CONCLUSIONS: The prevalence of fetal CNS anomalies was higher than previously reported in the literature for both symptomatic RT-PCR-positive and -negative pregnant women. Corpus callosum anomalies, microcephaly, neuronal migration disorders, and brain parenchymal hyperechogenicities were the most frequent CNS anomalies detected. In addition, CNS anomalies were more frequent and severe in infected fetuses during the first trimester of pregnancy than during the second or third trimester.

A Hybrid Genome Assembly Resource for Podosphaera xanthii, the Main Causal Agent of Powdery Mildew Disease in Cucurbits.

Podosphaera xanthii is the main causal agent of powdery mildew in cucurbits and, arguably, the most important fungal pathogen of cucurbit crops. Here, we present the first reference genome assembly for P. xanthii. We performed a hybrid genome assembly, using reads from Illumina NextSeq550 and PacBio Sequel S3. The short and long reads were assembled into 1,727 scaffolds with an N50 size of 163,173 bp, resulting in a 142-Mb genome size. The combination of homology-based and ab initio predictions allowed the prediction of 14,911 complete genes. Repetitive sequences comprised 76.2% of the genome. Our P. xanthii genome assembly improves considerably the molecular resources for research on P. xanthii-cucurbit interactions and provides new opportunities for further genomics, transcriptomics, and evolutionary studies in powdery mildew fungi.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Zika virus infection: A correlation between prenatal ultrasonographic and postmortem neuropathologic changes.

This study presents a correlation between prenatal ultrasonographic images and neuropathologic findings of postmortem tissue samples from five confirmed cases of perinatal Zika virus (ZIKV) infection belonging to the cohort of the ZEN Initiative in Bucaramanga, Colombia. Deaths occurred between June 2016 and March 2017. Mothers consulted with ZIKV infection clinical manifestations or fetal central nervous system (CNS) abnormalities or both. A detailed ultrasound scan and neurosonographic protocol was performed by maternal fetal specialists. Perinatal autopsies were performed following the Colombian National Health Institute's ZIKV protocol. The autopsies were from two fetal deaths, and three early neonatal deaths. Gestational age was between 262/7 and 382/7 weeks. Two cases were classified as mild microcephaly. Few findings by ultrasound and pathology were found in case 1 because it was a late infection; the other cases presented findings corresponding to congenital Zika syndrome: craniofacial malformations, cerebellar hypoplasia, anomalies of the corpus callosum and ventriculomegaly, all confirmed in autopsy specimens. By ultrasonography, hyperechogenicities were seen in several brain structures, which correspond to cortical and periventricular calcifications, subependymal glial reactivity and perivascular rings. The ultrasound and pathological findings show a wide spectrum of CNS anomalies that confirm the neurotropic effect of the ZIKV, recognizing the neuroimaging findings of this disease (unilateral ventriculomegaly, alterations in the corpus callosum and cerebellum, and calcifications) are highly suggestive of ZIKV infection.

[Conventional serum tumor markers in liver cancer. Retrospective analysis of 118 patients]. / Rendimiento diagnóstico de marcadores tumorales séricos convencionales en pacientes con sospecha clínica de cáncer primario metastásico a hígado.

BACKGROUND: Conventional serum tumor markers (CSTM) are widely used for monitoring patients with cancer. However, their usefulness as a diagnostic tool is controversial in primary or metastatic liver cancer (PMLC). AIM: To evaluate the diagnostic performance of the most commonly requested CSTM in the diagnostic approach of PMLC. MATERIAL AND METHODS: Review of medical records of patients aged over 18 years with a liver biopsy, attended from 2005 to 2017 in a tertiary hospital and a regional cancer center in Colombia. The results of liver biopsies were compared with tumor markers such as carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), CA 19-9, CA 125 and prostate specific antigen (PSA) using a receiver operating characteristic (ROC) curve analysis. RESULTS: We reviewed 2063 medical records and retrieved 118 eligible patients (59 cases and 59 controls, 70% males). Thirty percent had obstructive jaundice. There was heterogeneity in the amount of tumor markers requested according to medical criteria. Only CA 19-9 showed discriminative capacity (> 17.6 U/m), with a cut-off point lower than that reported in the literature and a sensitivity of 69.5%, specificity of 91.6%, a positive likelihood ratio (LR) of 8.32, and a negative LR of 0.33. CONCLUSIONS: Except for CA 19-9, tumor markers were not useful for the initial diagnostic approach in patients with suspected primary or metastatic malignant liver tumors.

The genetic variability and evolution of red-spotted grouper nervous necrosis virus quasispecies can be associated with its virulence.

Nervous necrosis virus, NNV, is a neurotropic virus that causes viral nervous necrosis disease in a wide range of fish species, including European sea bass (Dicentrarchus labrax). NNV has a bisegmented (+) ssRNA genome consisting of RNA1, which encodes the RNA polymerase, and RNA2, encoding the capsid protein. The most prevalent NNV species in sea bass is red-spotted grouper nervous necrosis virus (RGNNV), causing high mortality in larvae and juveniles. Reverse genetics studies have associated amino acid 270 of the RGNNV capsid protein with RGNNV virulence in sea bass. NNV infection generates quasispecies and reassortants able to adapt to various selective pressures, such as host immune response or switching between host species. To better understand the variability of RGNNV populations and their association with RGNNV virulence, sea bass specimens were infected with two RGNNV recombinant viruses, a wild-type, rDl956, highly virulent to sea bass, and a single-mutant virus, Mut270Dl965, less virulent to this host. Both viral genome segments were quantified in brain by RT-qPCR, and genetic variability of whole-genome quasispecies was studied by Next Generation Sequencing (NGS). Copies of RNA1 and RNA2 in brains of fish infected with the low virulent virus were 1,000-fold lower than those in brains of fish infected with the virulent virus. In addition, differences between the two experimental groups in the Ts/Tv ratio, recombination frequency and genetic heterogeneity of the mutant spectra in the RNA2 segment were found. These results show that the entire quasispecies of a bisegmented RNA virus changes as a consequence of a single point mutation in the consensus sequence of one of its segments. Sea bream (Sparus aurata) is an asymptomatic carrier for RGNNV, thus rDl965 is considered a low-virulence isolate in this species. To assess whether the quasispecies characteristics of rDl965 were conserved in another host showing different susceptibility, juvenile sea bream were infected with rDl965 and analyzed as above described. Interestingly, both viral load and genetic variability of rDl965 in seabream were similar to those of Mut270Dl965 in sea bass. This result suggests that the genetic variability and evolution of RGNNV mutant spectra may be associated with its virulence.

Cohort profile: Colombian Cohort for the Early Prediction of Preterm Birth (COLPRET): early prediction of preterm birth based on personal medical history, clinical characteristics, vaginal microbiome, biophysical characteristics of the cervix and maternal serum biochemical markers.

PURPOSE: Preterm birth (PTB) is a public health issue. Interventions to prolong the length of gestation have not achieved the expected results, as the selection of population at risk of PTB is still a challenge. Cervical length (CL) is the most accepted biomarker, however in the best scenario the CL identifies half of the patients. It is unlikely that a single measure identifies all pregnant women who will deliver before 37 weeks of gestation, considering the multiple pathways theory. We planned this cohort to study the link between the vaginal microbiome, the proteome, metabolome candidates, characteristics of the cervix and the PTB. PARTICIPANTS: Pregnant women in the first trimester of a singleton pregnancy are invited to participate in the study. We are collecting biological samples, including vaginal fluid and blood from every patient, also performing ultrasound measurement that includes Consistency Cervical Index (CCI) and CL. The main outcome is the delivery of a neonate before 37 weeks of gestation. FINDINGS TO DATE: We have recruited 244 pregnant women. They all have measurements of the CL and CCI. A vaginal sample for microbiome analysis has been collected in the 244 patients. Most of them agreed to blood collection, 216 (89%). By August 2021, 100 participants had already delivered. Eleven participants (11 %) had a spontaneous PTB. FUTURE PLANS: A reference value chart for the first trimester CCI will be created. We will gather information regarding the feasibility, reproducibility and limitations of CCI. Proteomic and metabolomic analyses will be done to identify the best candidates, and we will validate their use as predictors. Finally, we plan to integrate clinical data, ultrasound measurements and biological profiles into an algorithm to obtain a multidimensional biomarker to identify the individual risk for PTB.

Neurodevelopmental outcome of infants without central nervous system anomalies born to symptomatic RT-PCR ZIKV positive women.

An epidemic of Zika virus (ZIKV) infection began in Colombia in October 2015. Previous studies have identified a cause-effect relationship between fetal exposure to the ZIKV and the development of microcephaly and other central nervous system (CNS) anomalies with variable degrees of neurodevelopmental delay. Less is known about the neurodevelopmental outcome of infants without CNS anomalies born to symptomatic ZIKV RT-PCR-positive women. We aimed to compare the neurodevelopmental outcome of these infants to a control group of infants without CNS anomalies born to asymptomatic ZIKV RT-PCR negative women who did not seroconvert during pregnancy. Participating infants were categorized according to ZIKV maternal exposure. Women with symptomatology suggestive of ZIKV infection and a positive RT-PCR for ZIKV were categorized as ZIKV-exposed. Maternal controls (ZIKV unexposed) from the same geographic area were subsequently captured during the tail end of the epidemic through a partner project, the ZIKAlliance, whose aim was to determine the prevalence of ZIKV in pregnant women. Infant survivors from these two groups of pregnant women had a neurodevelopmental evaluation at 12, 18, and 24 months corrected age (CA). The ZIKV-exposed women were found to be older, had less subsidized health care, had a higher percentage of women in middle-class socioeconomic strata, had higher technical and university education, were less likely to be living with a partner, and had higher rates of pregnancy comorbidity and premature births than ZIKV unexposed women. Compared to infants born to ZIKV unexposed women (unexposed), infants born to ZIKV exposed women (exposed) were of lower gestational age and required more speech and occupational therapy services. No differences between groups were observed in the proportion of cut-off scores <70 on the Bayley-III Scale at 12, 18, and 24 months for motor, language, and cognitive domains. When a cut-off of <85 was used, a higher percentage of motor and cognitive impairment was observed in unexposed infants at 12 and 24 months CA, respectively. Median and IQR score on the Bayley-III scale showed higher scores in favor of exposed infants for motor development at 12 and 18 months CA, language at 12 months, and cognitive domain at 12, 18, and 24 months. The adjusted median and IQR compound score of the difference between exposed and unexposed was higher in favor of exposed infants at 12 to 24 months CA for motor (3.8 [95% CI 1.0 to 6.7]) and cognitive domains (10.6 [95% CI 7.3 to 13.9]). We observed no differences in the language domain (1.9 [95% CI -1.2 to 5.0]). We conclude that infants with no evidence of microcephaly or other CNS anomalies born to ZIKV-exposed women had normal neurodevelopment up to 24 months of CA, supporting an all-or-nothing effect with maternal ZIKV exposure. Long-term follow-up to evaluate school performance is required. Clinical Trial Registration: www.clinicaltrials.gov, NCT02943304.

Complex Congenital Heart Disease and Neurodevelopment. A Case Study of Fraternal Twins.

Congenital heart defects have been associated with adverse neurodevelopmental outcomes due to factors that result in a hypoxic-ischemic cerebral cumulative effect. We present a pair of fraternal twins: the first twin was healthy, and the second was born with a complex congenital heart defect (CCHD). They were followed for growth and neurodevelopmental outcomes to determine the comparative effect of exposure to a CCHD. Results show that exposure to a CCHD could be related to a persistent motor deficiency with hypotonia and concurrent height for age delay. CCHD requires a comprehensive neurodevelopmental approach; the pathophysiology and the surrounding stimuli are influential.

Design and validation of the ECAVINAE-LICCE scale to evaluate quality of life in children and adolescents with epilepsy.

OBJECTIVE: To design and validate a scale to evaluate the quality of life in children and adolescents with epilepsy. METHODS: Scale validation, multicentered, three-phase study. We did a literature review for the construction of the instrument, and a validation of appearance, construct, criterion, and reproducibility. We evaluated the scale among the patients that consulted at the Liga Central contra la Epilepsia and the Fundación Hospital de La Misericordia (Bogotá, Colombia) between 2014 and 2015. RESULTS: The resulting questionnaire has 4 domains, with 18-26 items according to age groups (0-3, 4-10 and 11-17 years old) and a Likert scale score from 1 to 5. The comparison with CAVE and QOLIE AD 48 was adequate (Pearson correlation coefficient between 0.713 and 0.837 according to age groups: intraclass correlation coefficient between 0.664 and 0.817.) Internal consistency was adequate (Cronbach's alpha between 0.791 and 0.809). Test-retest assessment was good, with Spearman's coefficient between 0.99 and 1.00. The time to fill out the scale ranged between 3.5 and 6.8 min. SIGNIFICANCE: We designed and validated a quality-of-life scale in Spanish for children and adolescents with epilepsy, which is easy and quick to fill and has excellent reliability and validity parameters.

Chemical interplay and complementary adaptative strategies toggle bacterial antagonism and co-existence.

Bacterial communities are in a continuous adaptive and evolutionary race for survival. In this work we expand our knowledge on the chemical interplay and specific mutations that modulate the transition from antagonism to co-existence between two plant-beneficial bacteria, Pseudomonas chlororaphis PCL1606 and Bacillus amyloliquefaciens FZB42. We reveal that the bacteriostatic activity of bacillaene produced by Bacillus relies on an interaction with the protein elongation factor FusA of P. chlororaphis and how mutations in this protein lead to tolerance to bacillaene and other protein translation inhibitors. Additionally, we describe how the unspecific tolerance of B. amyloliquefaciens to antimicrobials associated with mutations in the glycerol kinase GlpK is provoked by a decrease of Bacillus cell membrane permeability, among other pleiotropic responses. We conclude that nutrient specialization and mutations in basic biological functions are bacterial adaptive dynamics that lead to the coexistence of two primary competitive bacterial species rather than their mutual eradication.

Sporulation is dispensable for the vegetable-associated life cycle of the human pathogen Bacillus cereus.

Bacillus cereus is a common food-borne pathogen that is responsible for important outbreaks of food poisoning in humans. Diseases caused by B. cereus usually exhibit two major symptoms, emetic or diarrheic, depending on the toxins produced. It is assumed that after the ingestion of contaminated vegetables or processed food, spores of enterotoxigenic B. cereus reach the intestine, where they germinate and produce the enterotoxins that are responsible for food poisoning. In our study, we observed that sporulation is required for the survival of B. cereus in leaves but is dispensable in ready-to-eat vegetables, such as endives. We demonstrate that vegetative cells of B. cereus that are originally impaired in sporulation but not biofilm formation are able to reach the intestine and cause severe disorders in a murine model. Furthermore, our findings emphasise that the number of food poisoning cases associated with B. cereus is underestimated and suggest the need to revise the detection protocols, which are based primarily on spores and toxins.

Dual functionality of the amyloid protein TasA in Bacillus physiology and fitness on the phylloplane.

Bacteria can form biofilms that consist of multicellular communities embedded in an extracellular matrix (ECM). In Bacillus subtilis, the main protein component of the ECM is the functional amyloid TasA. Here, we study further the roles played by TasA in B. subtilis physiology and biofilm formation on plant leaves and in vitro. We show that ΔtasA cells exhibit a range of cytological symptoms indicative of excessive cellular stress leading to increased cell death. TasA associates to the detergent-resistant fraction of the cell membrane, and the distribution of the flotillin-like protein FloT is altered in ΔtasA cells. We propose that, in addition to a structural function during ECM assembly and interactions with plants, TasA contributes to the stabilization of membrane dynamics as cells enter stationary phase.

Pentraxin-3 is a candidate biomarker on the spectrum of severity from pre-eclampsia to HELLP syndrome: GenPE study.

Pentraxin-3 has been reported as a promising biomarker of pre-eclampsia and its severity; however, available studies have small sample sizes, and analyses are not always adjusted for confounders. The aim of this study is to establish the strength of the association between maternal Pentraxin-3 level and pre-eclampsia or HELLP syndrome. It was a case-control study. Women with pre-eclampsia or HELLP syndrome were defined as cases, and women with healthy pregnancies at term (>37 weeks) were classified as controls. Plasma concentrations of Pentraxin-3 were determined at the time of delivery by quantitative enzyme immunoassay. Associations between Pentraxin-3 and pre-eclampsia and HELLP syndrome were assessed by multinomial logistic regression. Subsidiary analysis for the time of disease onset was also carried out. Odds ratios and 95% confidence intervals are reported. A total of 1024 pregnant women were included (461 controls, 368 pre-eclampsia, 195 HELLP). A positive log-linear relationship was found between the top pentraxin-3 quintile and HELLP syndrome. After adjustment for confounders (maternal age, ethnicity, socioeconomic position, date and place of recruitment, family history of pre-eclampsia, smoking, body mass index at beginning of pregnancy, gestational age and multiple pregnancy), the strength of the association was higher for HELLP syndrome [OR 1.13 (95% CI 1.08; 1.18)] than for pre-eclampsia [OR 1.03 (95% CI 1.03; 1.10)]. No difference according to time of onset or pentraxin-3 level was found. In summary, pentraxin-3 level was associated with pre-eclampsia, but it was more strongly associated with HELLP syndrome. Longitudinal studies with a lower probability of residual confounding are necessary to improve our knowledge about the role of pentraxin-3 in pre-eclampsia.

Daily cigarette smoking among Colombian high school students: gender related psychosocial factors.

This study aimed to establish the prevalence of daily cigarette smoking (DCS) and its gender correlated factors in high-school attending adolescents from Bucaramanga, Colombia. A random cluster sample was surveyed (N = 2291). The previous month DCS prevalence was 11.6% (95% CI 9.7-13.5) in boys and 4.4% (95% CI 3.3-5.5) in girls. In girls, DCS was associated with previous month illegal substance use (OR 8.13, 95%CI 3.52-18.87), abusive alcohol consumption (OR 5.88, 95% CI 2.54-13.70), being the best friend of a smoker (OR 3.25, 95% CI 1.38-7.63), and poor or mediocre academic achievement (OR 2.46, 95% CI 1.25-4.85). In boys, DCS was related to previous month substance use (OR 6.23, 95% CI 3.62-10.71), being the best friend of a smoker (OR 5.87, 95% CI 2.93-11.76), poor or mediocre academic achievement (OR 2.09, 95% CI 1.34-3.24), and being older than non-smokers (OR 1.48, 95% CI 1.21-1.81). DCS presents associated factors very similar for girls and boys. Thus, more research is needed.

Lethal mutagenesis of an RNA plant virus via lethal defection.

Lethal mutagenesis is an antiviral therapy that relies on increasing the viral mutation rate with mutagenic nucleoside or base analogues. Currently, the molecular mechanisms that lead to virus extinction through enhanced mutagenesis are not fully understood. Increasing experimental evidence supports the lethal defection model of lethal mutagenesis of RNA viruses, where replication-competent-defectors drive infective virus towards extinction. Here, we address lethal mutagenesis in vivo using 5-fluorouracil (5-FU) during the establishment of tobacco mosaic virus (TMV) systemic infections in N. tabacum. The results show that 5-FU decreased the infectivity of TMV without affecting its viral load. Analysis of molecular clones spanning two genomic regions showed an increase of the FU-related base transitions A → G and U → C. Although the mutation frequency or the number of mutations per molecule did not increase, the complexity of the mutant spectra and the distribution of the mutations were altered. Overall, our results suggest that 5-FU antiviral effect on TMV is associated with the perturbation of the mutation-selection balance in the genomic region of the RNA-dependent RNA polymerase (RdRp). Our work supports the lethal defection model for lethal mutagenesis in vivo in a plant RNA virus and opens the way to study lethal mutagens in plant-virus systems.

Differential Shape of Geminivirus Mutant Spectra Across Cultivated and Wild Hosts With Invariant Viral Consensus Sequences.

Geminiviruses (family Geminiviridae) possess single-stranded circular DNA genomes that are replicated by cellular polymerases in plant host cell nuclei. In their hosts, geminivirus populations behave as ensembles of mutant and recombinant genomes, known as viral quasispecies. This favors the emergence of new geminiviruses with altered host range, facilitating new or more severe diseases or overcoming resistance traits. In warm and temperate areas several whitefly-transmitted geminiviruses of the genus Begomovirus cause the tomato yellow leaf curl disease (TYLCD) with significant economic consequences. TYLCD is frequently controlled in commercial tomatoes by using the dominant Ty-1 resistance gene. Over a 45 day period we have studied the diversification of three begomoviruses causing TYLCD: tomato yellow leaf curl virus (TYLCV), tomato yellow leaf curl Sardinia virus (TYLCSV) and tomato yellow leaf curl Malaga virus (TYLCMaV, a natural recombinant between TYLCV and TYLCSV). Viral quasispecies resulting from inoculation of geminivirus infectious clones were examined in plants of susceptible tomato (ty-1/ty-1), heterozygous resistant tomato (Ty-1/ty-1), common bean, and the wild reservoir Solanum nigrum. Differences in virus fitness across hosts were observed while viral consensus sequences remained invariant. However, the complexity and heterogeneity of the quasispecies were high, especially in common bean and the wild host. Interestingly, the presence or absence of the Ty-1 allele in tomato did not lead to differences in begomovirus mutant spectra. However, the fitness decrease of TYLCSV and TYLCV in tomato at 45 dpi might be related to an increase in CP (Coat protein) mutation frequency. In Solanum nigrum the recombinant TYLCMaV, which showed lower fitness than TYLCSV, at 45 dpi actively explored Rep (Replication associated protein) ORF but not the overlapping C4. Our results underline the importance of begomovirus mutant spectra during infections. This is especially relevant in the wild reservoir of the viruses, which has the potential to maintain highly diverse mutant spectra without modifying their consensus sequences.

[Substance abuse amongst adolescents, Bucaramanga, Colombia, 1996-2004]. / Consumo de Sustancias Psicoactivas en Adolescentes, Bucaramanga, Colombia, 1996-2004.

OBJECTIVES: Ascertaining substance use prevalence amongst upper-level high-school adolescents and comparing these figures with those from 1996 and 1997. METHOD: 2,291 randomly sampled high-school adolescents participated in a cross-sectional survey about legal and illegal substance abuse. RESULTS: Mean adolescent age was 15,9 (1,09 SD); 53,9 % of the sample was female. The use of several substances grew from 1996/1997 to 2004, i.e. marihuana (1,5 % to 4,4 %), crack (0,.4 % to 1,2 %), inhalants (0,1 % to 1,2 %), stimulants (0,7 % to 1,9 %), and tranquilisers (2,0 % to 3,1 %). Similar figures were found for weekly alcohol use to the point of getting drunk (6,5 % to 7,7 %). Annual MDA use was 2,5 % (a substance not studied in 1996/1997). CONCLUSION: Inhalant and tranquiliser consumption amongst high-school adolescents has increased dramatically during the last few years. MDA consumption has reached a significant percentage.